package com.system.common.util;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class ExpiryMap {
    //存储数据的容器
    private Map<String,Object> map = new HashMap<>();
    //存储数据的有效期
    private Map<String,Long> expiryMap = new HashMap<>();

    //检查过期线程（池）
    private ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();

    //检查周期
    private long expiryTime = 1000*60;

    public ExpiryMap(){
        service.scheduleAtFixedRate(this::clearExpiry,expiryTime,expiryTime, TimeUnit.MILLISECONDS);

    }

    public ExpiryMap(long expiryTime){
        this.expiryTime=expiryTime;
        service.scheduleAtFixedRate(this::clearExpiry,expiryTime,expiryTime, TimeUnit.MILLISECONDS);

    }

    public void put(String key,Object value){
        map.put(key,value);
        expiryMap.put(key,System.currentTimeMillis()+expiryTime);
    }

    public void put(String key,Object value,long expiryTime){
        map.put(key,value);
        expiryMap.put(key,System.currentTimeMillis()+expiryTime);
    }

    public Object get(String key){
        if (expiryMap.get(key)!=null&&expiryMap.get(key)<System.currentTimeMillis()){
            map.remove(key);
            expiryMap.remove(key);
        }
        return map.get(key);
    }

    public boolean containsKey(String key){
        if (expiryMap.get(key)!=null&&expiryMap.get(key)<System.currentTimeMillis()){
            map.remove(key);
            expiryMap.remove(key);
        }
        return map.containsKey(key);
    }


    //清楚已经过期的key
    public void clearExpiry(){
        for (String key : expiryMap.keySet()) {
            if (expiryMap.get(key)!=null&&expiryMap.get(key)<System.currentTimeMillis()){
                map.remove(key);
                expiryMap.remove(key);
            }
        }
    }
}
